error confirm order

Hello again,
Somebody knows what mean that??
Warning: Call-time pass-by-reference has been deprecated - argument passed by value; If you would like to pass it by reference, modify the declaration of [runtime function name](). If you would like to enable call-time pass-by-reference, you can set allow_call_time_pass_reference to true in your INI file. However, future versions may not support this any longer. in /var/www/vhost/saiton.com/home/html/store/catalog/controller/checkout/confirm.php on line 49

Thanks for your help

I see this is a really old post, but encase anyone else needs to know:

add to your php.ini file, if you are using php 5 you may have to rename php.ini to php5.ini.